DE2744189A1 - METHOD FOR IMPROVING THE WEAR PROPERTIES OF IRON METAL PARTS - Google Patents

Description

27AA189

The invention relates to a method for improving the wear properties of ferrous metal parts with a thermal conductivity, measured at room temperature, with respect to silver of at least 0.06 cal ^{/ cm 2} / cm / ° C / sec., If the conductivity of the silver is set to 1, by creating a 0.0127 to 0.3810 cm thick protective layer made of a self-propagating heat and corrosion-resistant alloy based on a metal of the iron group or based on copper. The invention also relates to ferrous metal parts which are provided with a protective layer of the type described.

Components and structural elements of industrial plants and devices which are exposed to the action of heat during their operation and which are subject to corrosion and / or erosion and which are subject to normal wear, such as parts of heat exchangers, generally require constant maintenance and care to keep them operational. Such structural elements and components are generally made of ferrous metals, for example soft steels and low-alloy steels, cast iron, wrought iron and the like. The construction elements and components can have a wide variety of shapes, for example from vents and hoods of converters, walls, baffle and baffle plates, fan parts and fan blades as well as linings of Lrz sintering furnaces, superheater and preheater pipes of boilers of power plants as well as ferrous metal parts of incinerators , for example, incinerators and the like exist.

Previously it was common to be worn or corroded or eroded Replacing parts with new parts, with the amount of time required to date the metal part in question replacing which, of course, would increase maintenance costs. Recently, however, the cost of that have to be spent on replacing individual parts of devices and systems is constantly increasing, due to constantly rising manufacturing and wage costs.

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There has therefore been no lack of attempts to identify the parts subject to wear and the worn or corroded or eroded parts with an erosion, corrosion, hitie- and to coat oxidation-resistant alloy, in particular by spraying a corresponding alloy onto the Surface of the metal part to be protected and melting or melting the applied coating mass together.

Although the methods that have become known lead to a certain protection of the parts to be protected, it has been shown that that the previously known coatings do not yet meet all the requirements that a protective metal layer must meet, suffice. For example, iron metal substrates, for example cast iron, soft iron, wrought iron, show low-alloyed ones Steels and the like have good thermal conductivity for such materials of over about 0.1 quai./cm / cm/°C/sec, AU&t for example up to 0.2 (in the case of wrought iron), which is important in many cases when the metal part is in contact with a heat supplier or a heat source, for example in the case of a heat exchanger.

If, for example, is applied to the surface of a ferrous metal substrate, for example, on the surface of a cast iron part, a coating of stainless steel, such as steel of the type, is applied 410, for example by spraying on, the cast iron part is in no way effectively protected and the protective layer in no way has the desired properties. So did the applied Layer initially has an adverse effect on the thermal conductivity, which is of great importance, for example, in the case of heat exchanger surfaces. The thermal conductivity of the applied layer is namely below 0.06 Kai./cm / cm / C / sec., although the thermal conductivity of cast iron is over 0.1.

While heat-resistant nickel-based alloys are advantageous coating compounds, most heat-resistant nickel alloys have low thermal conductivity.

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For example, a commercially available alloy (trade name Inconel) with 13 to 15 I Cr, 6 to 8 t Fe and the remainder nickel has a thermal conductivity at room temperature of about 0.035, which is considerably below the thermal conductivity of cast iron and low-alloy steels. A nickel-based alloy with 60 % Ni, 24 t Fe and 16 % Cr has a thermal conductivity of about 0.032, which is also very low. An alloy based on cobalt with 25 to 30 \ Cr, 1.5 to 3.5 % Ni, 4.5 to 6.5 t Mo, a maximum of 2 % Fe, 0.2 to 0.35 % C and the remainder cobalt a thermal conductivity at 200 ^° C. of about 0.035. An alloy with 20 to 22.5 % Cr, 19 to 21 % Ni, 2.5 to 3.5 % Mo, 2 to 3 % W, 18.5 to 21 % Co, 0.75 to 1.25 % Nb + Ta, 0.1 to 0.2 % N, maximum 0.2 % C and the remainder iron has a thermal conductivity at 20O ⁰ C of about 0.035.

On the other hand, practically pure nickel shows a thermal conductivity of about 0.22. However, if chromium is added to the nickel metal matrix as a dissolved substance, for example in an amount of 15 or 20 % , the thermal conductivity of the nickel falls drastically to a value below 0.5, for example in the order of 0.03 to 0.04 cal ./cni ² / cm / ° C / sec. For example, an alloy with 80 % Ni and 20 % Cr has a thermal conductivity at 100 ^° C. of 0.032. Pure cobalt has a conductivity at room temperature of about 0.165. However, if chromium is added as a dissolved metal, for example in amounts of more than 10 %, the thermal conductivity is drastically reduced.

Thus becomes a heat and oxidation resistant layer from a Low conductivity alloy on a ferrous metal substrate applied with a thermal conductivity of at least 0.06, so the thermal conductivity of the coated material is adversely affected by the applied layer.

There is therefore a need for alloys that can be used

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Layers of ferrous metal substrates are suitable and have the necessary chemical and physical properties, so that thermal conductivities of at least about 0.05 Kai./cm ² / cm / ° C / sec. and up to 0.08 and above can be achieved.

The object of the invention is therefore, heat, corrosion, erosion and to specify oxidation-resistant alloys for the production of protective layers on metal substrates, which by a thermal conductivity of at least 0.05 cal / cm / cm / ° C / Sec. Are marked.

The invention was based on the knowledge that the problem can be solved by increasing the concentration of certain Alloy constituents consisting of so-called poorly fusible or refractory dissolved metals, e.g. Tungsten, molybdenum and chromium, and which normally adversely affect the thermal conductivity of the alloy to be produced, controls carefully.

It has been found that certain self-fluxing alloys are particularly suitable for solving the problem posed, namely alloys based on iron, nickel, cobalt and copper. The alloys contain about 0.5 to 5 % boron and 0.1 to 6 % silicon and up to about 3 % carbon in combination with strong carbide! Boride binders from the group of dissolved metals, ie metals that are difficult to melt or heat-resistant, such as tungsten and / or molybdenum and / or chromium. An essential advantage of the self-moving alloys is that they provide protective metal layers or metal layers which are self-healing at elevated temperatures.

The invention accordingly provides a method for improvement the wear properties of Eiscnmetallteilecn with a thermal conductivity measured at room temperature SiII) Or of at least 0.00 cal / cm / cm / ° C / sec., If the Conductivity of silver is set at 1 by generation

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a 0.0127 to 0.3810 cm thick protective layer made of a self-running heat and corrosion-resistant alloy based on a metal of the iron group or based on copper, which is characterized in that, starting from an alloy containing up to 30 wt . -I, for example 1 to 30% by weight, W, Mo and / or Cr and optionally 0.1 to 6% by weight of Si, and up to 3% by weight of C and / or 0.5 up to 5% by weight of B is added, the B and / or C content being such that at least 70 % of the metals W, Mo and / or Cr are present in bonded form in the form of secondary borides and / or secondary carbides, a protective layer with a thermal conductivity measured at room temperature, with respect to silver, if the conductivity of the silver is set to 1, of at least 0.05 cal / cmV cm / ° C / sec. generated.

The invention also relates to a ferrous metal part with an alloy of the specified composition generated coating.

According to the method of the invention, ferrous metal substrates with a thermal conductivity, measured at room temperature, of at least about 0.06 Kai./cm2/cm/°C/sec. xuood metallurgically bound heat, corrosion, erosion and Apply oxidation-resistant alloys based on metals of the iron group and copper-based, which have a thermal conductivity of at least about 0.05 Kai./cm^/cm/°C/Sec. Marked are.

The drawing serves to explain the invention in more detail. In detail are shown in:

1 shows a fragment of a coated ferrous metal part produced by the method of the invention in section, e.g. a fragment of a heat exchanger element made of cast iron with a layer of a Nickel alloy that has entered into a metallurgical bond with the substrate, the applied alloy

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layer has a thermal conductivity of at least about 0.06;

2 shows a section through a further section of a heat exchanger element made of a low-alloy steel with a layer of an alloy applied to it based on cobalt, which is metallurgically bonded to the steel substrate, the layer being made of the cobalt alloy has a thermal conductivity of at least about 0.06;

3 shows a section through a section of a coated metal substrate, similar to that shown in FIG with the exception, however, that the metal substrate in this case consists of cast iron and the applied layer consists of a Layer of a nickel alloy is and

Fig. 4 is a section through a portion of a coated part made of a carbon steel with an alloy is coated on an iron base, which is metallurgically bonded to the phthalic substrate.

By carefully controlling the relationship between the dissolved metals tungsten, molybdenum and chromium, in particular chromium on the one hand and the boron present in the alloy metal and Chromium is the proportion of dissolved metal, i.e. the proportion of metal that is a solution with the dissolving metal iron, nickel, cobalt or forms copper, kept below the proportion that detrimentally affects the thermal conductivity of the metal in solution, for example nickel influenced.

For example, an alloy of 15% Cr, 7 \ Fe and the balance nickel, a comparatively low thermal conductivity of about 0.035 in, in Minblick to the presence of Cr and Fe. By reducing the amount of Cr dissolved in the nickel matrix by converting a substantial portion of the chromium into a carbide or boride so that there is no solid solution with the nickel

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forms more, the thermal conductivity of the alloy is increased, at least to about 0.05 and above, creating a Metal layer is created, due to improved resistance is marked against erosion, corrosion, wear and oxidation.

If the alloy consists, for example, of a nickel-based alloy with 20 % Cr and 80 % Ni, the addition of about 3 % C and 2 % B leads to the consumption of a considerable proportion of the chromium with the formation of the carbide Cr-C ^ and the boride CrB, whereby the chromium of the compounds is in equilibrium with the remaining chromium, which is dissolved in the nickel matrix, due to the law of mass action.

What has been said about chromium also applies to the dissolved metals tungsten and molybdenum.

In an advantageous manner, according to the invention, an iron metal substrate can thus be used that has a thermal conductivity with respect to silver, which is assumed to be 1, of at least about 0.06 Ka1./cm / cm / ° C / sec. with a protective layer made of a self-moving (self-fluxing) Coating heat and corrosion resistant metal alloy from a metal of the iron group, which has a thickness of about 0.0127 to 0.38 cm, in particular 0.0254 to 0.203 cm.

The alloy metal of the iron group contains 0 to a total of 30% by weight, for example 1 to about 30% by weight, of at least one metal which forms a boride and carbide and consists of tungsten, molybdenum and chromium (preferably at least about a total of about 30% by weight ) ). Furthermore, the alloy contains up to about 3 % C, about 0.5 to 5 % B and preferably about 0.1 to (i % Si. The remainder of the alloy is made up of iron, nickel and cobalt or copper.

The concentration of carbon and boron in the alloy will be

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dimensioned such that a substantial proportion of the metal tungsten, molybdenum and / or chromium with the carbon and / or Hearing converts, so that the alloy layer is characterized by a thermal conductivity that is relative at room temperature compared to silver, the conductivity of which is set at 1, a conductivity of at least 0.05 Kai./cm^/cm/°C/sec. having.

Examples of alloys which are used according to the invention are listed in Tables 1, 2 and 3 below.

Table 1 Nickel-based alloys

Wt- ° 6

Si

Cr

Mon

Ni

1 1.5 2 1 , 5 - T 5 3 - rest 2 - 2.5 2 (NJ lt-Basi 15th - - rest 3 1 1 1 - 10 5 rest 4th (Nl 1 , 5 - 20th - - rest 5 1 1 3 - 5 15th rest 6th 2 2 10 - 10 rest 7th achieved 4th - 18th - - rest abelle 2 Legi on Koba S.

Weight %

No. Si

Cr

Mon

Co

8th 1 1 (NJ 15th - - 5 rest 9 - 2 3 - - 15th 8th rest 10 2 2 - 18th - - - rest 11 1 (NJ 2 10 5 rest (NJ 1.5 3 1 - 10 rest 13th 3 2 0.5 12th 5 rest

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Table 3 Iron-based alloys

Weight I

No.

Si

Mon

14th 1 5 1 5 2 15th - - rest 15th 3 5 2 5 - 10 5 - rest 16 2 2 1 - 15th 5 rest 17th 1 3 1 10 - 10 rest 18th 2 2 1 20th 5 - rest 19th O, 2, - - 5 10 rest 20th 1, 1, 2 10 - 10 rest

A self-fluxing alloy on the basis of a ferrous metal thus contains advantageously from 0.1 to 6% Si, 0.5 to 5 \ B and up to 3 tonnes of carbon, the remainder being iron, nickel or cobalt. In the case of iron-based alloys, nickel and / or cobalt can also form alloy components as long as their concentrations do not lower the thermal conductivity of the iron alloy below 0.05. In corresponding catfish, for example, a nickel-based alloy can also contain iron and / or nickel. Finally, an alloy based on cobalt can also contain nickel and iron, with the rule in each case that the thermal conductivity of the alloy should not be suppressed below 0.05.

Alloy No. 2 listed in Table 1 contains, for example, 2 IB, 2 \ C and 15 X Cr. Since chromium forms borides and carbides, a comparatively considerable proportion of the dissolved metal chromium is removed from the solution with the nickel matrix after the layer has been applied to the ferrous metal substrate and melted. Due to the law of mass action, the chromium is redistributed between the matrix and the boride and / or carbide reaction product, the mass of the chromium in the nickel matrix being reduced to significantly below 10 wt. T

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e.g. to 5 1 or below, reducing the thermal conductivity the alloy layer is improved with respect to the ferrous metal substrate.

The concentration of boron and / or carbon in the alloy is such that about 70 % or more of the dissolved metal is bound in the form of compounds, so that this metal component can no longer enter into a solid solution with the matrix alloy. Advantageously, the concentration of dissolved metal in the matrix is well below 10 %.

Certain metal carbides and metal borides have good thermal properties Conductivities of at least about 0.05. So in some cases a twofold effect can be achieved, namely: 1. one Improvement of the thermal conductivity of the matrix alloy and 2. the formation of a metal compound, i.e. a compound of chromium, tungsten or molybdenum, which itself has an advantageous thermal conductivity.

A particularly advantageous copper-based alloy is, for example one without zinc, for example the composition shown in the following table:

Copper bas labelIe 4th Particular advantage area > Alloys on Br e is more liable 25.0 component I 15.0 - 4.0 10, iter area 2.0 - 1.0 nickel 1, 0.25 - 1.0 Silicon O, 0 - 0.2 - boron 0, 0 - (1 manganese 1 - copper 2 - ( ■ 40.0 • 5.0 ■ 2.5 ■ 2.0 :O

(1) remainder

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Advantageously, a matrix alloy on copper Based on, for example, the following composition:

Table 5 Gew.-S component 23.00 nickel 3.45 silicon 0.47 boron 0.75 manganese (U copper

(I) residual component

Another advantageous copper-based alloy is, for example, one having 1.5 wt -.% Ni, 0.3 wt .- *, Cr, 0.1 wt '"Si, 0.1 wt .- * B, 0 , 3 wt. IP, 0.02 wt. ⁴ »C, 7.7 wt. % Sn and the remainder copper.

When creating a metallurgically bonded alloy layer on a ferrous metal substrate, for example a heat exchange element, the substrate is first cleaned in a conventional manner. After that, the substrate surface can be more advantageous Be prepared further, for example by irradiation with cleaning or abrasive particles by means of a blower, for example by inflating particles with a particle size of +25 mesh (plus 25 mesh), for example of quenched Cast iron.

Advantageously, they have for the production of the upper layers Alloys used such a composition that melting points of up to about 1371 ° C, advantageously for example from about 983 to 1233 ° C can be reached. The melting points can advantageously be determined by the concentration control of silicon and boron.

The layers can be covered in an advantageous manner by flame

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spray coating of alloy powders (e.g. atomized powder) Apply to the ferrous metal surface. The powder particles can advantageously have a particle size of -125 microns to about 40 microns, i.e. less than 125 Mesh up to about 400 mesh according to U.S. Default.

For applying the powder coating material to the ferrous metal surfaces, e.g. steel surfaces, for example flame spray devices such as those disclosed in U.S. Patents can be used 3,226,028, 3,262,644, and 3,273,800 are known. There is a particularly advantageous device for producing the protective layers from a gravity sprayer of the type known from U.S. Patent 3,620,454. Another beneficial one Spray device is known, for example, from U.S. Patent Application Serial Number 643,823 filed Dec. 23, 1975.

The spray device from the last-mentioned patent is particularly advantageous when the alloy powder is first sprayed onto the ferrous metal substrate, followed by melting or fusion. The spray devices, which are described in the first three patents can be used in an advantageous manner when a simultaneous spraying and melting should take place. The metal substrate can advantageously be preheated.

Advantageously, the alloy coating can thus after the flail spray process onto a preheated metal surface be applied, after which the applied layer of action exposed to a flame from an oxygen-acetylene burner, whereupon the applied layer on the surface, e.g. a raw or pipe part, is melted.

Tests with about 0.0254 cm thick layers showed a considerable one improved service life compared to unprotected substrates. The method of the invention thus enables a considerable amount Cost savings. It has been shown that advantageous

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Results are then obtained when the layer thickness is on the metal surface applied layers at about 0.01270 to 0.38 cm, for example 0.0254 to 0.2032 cm, in particular is about 0.0254 to 0.1270 cm.

In the case of FIG. 1, the nickel-based alloy consists of an alloy with about 1% by weight of Si, 2% by weight of B, 1% by weight of C, 15 wt. T of Cr and the remainder of nickel. The ferrous metal substrate consists of a heat exchange element made of cast iron with 1.5 Wt. T Si, 0.57 wt. T Mn, 3.16 wt. T total carbon and the remainder of iron. The ferrous metal substrate had a thermal one Conductivity of about 0.11.

The surface of the element was made in a conventional manner cleaned, whereupon the surface was further cleaned by blown irradiation with cast iron particles. Then the Alloy particles are sprayed onto the surface and melted by directing a burner flame onto the applied layer. In this way a layer 0.063 cm thick was produced. Chromium compounds, i.e. carbides and borides, were formed during melting and cooling, so that about 70 tons or more of the chromium were prevented from going into solution, i.e. a with the matrix metal from forming a solution. To this In this way, a top layer with a thermal conductivity of over 0.05 was obtained.

The heat exchange element shown schematically in Fig. 2 consists of a low-alloy steel substrate with a Alloy based on cobalt was coated with 1 wt. T Si,

2 tons by weight B, 3 tons by weight C, 25 tons by weight Cr, 3 tons by weight Ni, 4.5 tons by weight W,

3 tonnes by weight of Mo and the remainder of cobalt. The low-alloy steel substrate contained 0.34% by weight of C, 0.55% by weight of Mn, 0.78% by weight of Cr, 3.53 wt. T Ni, 0.39 wt. T Mo, 0.05 wt. T Cu, while the remainder consisted of iron. The steel had thermal conductivity of about 0.079.

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The heat exchanger part was cleaned again, whereupon the alloy was sprayed onto the metal part and melted by directing a burner at the applied layer to produce a high-density melted layer. The layer produced in this manner is characterized by a cobalt alloy matrix, are dispersed in the borides and carbides, wherein the proportion of chromium in solution considerably less than 10 wt -% is under achieving an optimum thermal conductivity of at least 0.05..

In the case of FIG. 3, the substrate consists of a wrought iron substrate, while the applied layer is a layer based on a nickel alloy. The substrate has a thermal conductivity of 0.2. The nickel-based alloy containing 3 weight-O Si, 2 wt -. \ B, 5 parts by weight of l Cr and 5 wt .- *. Mo. The remainder consisted essentially of nickel. The alloy was applied as in the case of the material shown in FIG. The applied layer had the desired thermal conductivity due to the formation of borides of the metals chromium and molybdenum.

In the case of Fig. 4, the ferrous metal substrate consisted of a part made of carbon steel with 1.22 wt .- * »C, 0.35 wt .- * Mn (remainder Iron) with a thermal conductivity of about 0.124. The iron-based alloy applied contained about 3% by weight of Si, 2 parts by weight of B, 10% by weight of Cr and 5% by weight of Mo (remainder essentially Iron). The layer was applied as described in connection with FIG. 1.

Examples of further advantageous alloys for carrying out the method of the invention are:

(1) alloy with 0.7 part by weight Ί C, 15 wt -. \ Cr, 4.3 part by weight I Si, 3.7 part by weight l Fe, 3.4 wt ⁰ »B (residual Nickel);

(2) Alloy with 0.4% by weight of IC, 2% by weight of IB, 4% by weight of Si, 3.5% by weight of Fe, 11% by weight of \ Cr (balance nickel) and

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(3) Alloy with 1.5% by weight Ni, 0.3% by weight Cr ^{, 0.1% by weight 7th} Si, 0.1% by weight *. B, 0.3% by weight . IP, 0.02 ^wt? C and 7.7 part by weight I Sn (balance copper).

As stated earlier, as a result of the merging Carbides and borides "in situ" in the matrix of the alloy layers generated, through which the thermal conductivity of the matrix metal of the layers is improved. Such carbides and borides that are formed by reaction in the layer can be referred to as secondary carbides and borides.

However, it is also possible to adjust the wear properties and To further improve the resistance of the alloy layers, the alloy powders before spraying onto a Liseiuiietallunterlage to add so-called primary carbides.

Such primary carbides include, for example, carbides of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo and W. The alloy powder can be mixed with up to about 80% by weight of such primary carbides for example with 5 to 70% by weight of primary carbides.

Preferably, to carry out the method of the invention atomized self-fluxing alloy powder used to spray on the layers. In an advantageous manner the atomized powders have a particle size of less than 100 mesh (U.S. Standard). A beneficial powder is one those that pass through a 100-mesh screen and of which at least 30% by weight pass through a 325-mesh screen. In case of use Of primary metal carbides, those which pass a 100 mesh screen are also preferably used, with at least Pass 30% by weight through a 325 mesh sieve. The primary carbides in the layers preferably have a particle size of less than 100 microns, for example less than 50 microns.

Examples of spray-on alloy powders with primary carbides

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are those with the following composition:

(1) 83% by weight of a nickel-based alloy with 17% by weight of primary tungsten carbide less than 50 microns in size, the nickel-based alloy being 0.7% by weight IC, 15% by weight Cr, . 4.3 parts by weight I Si, 3.7 wt -% Fe, 3.4 part by weight of t B, and the balance nickel;

(2) 40% by weight of a nickel-based alloy and 60% by weight of primary tungsten carbide, the nickel-based alloy consisting of 0.05% by weight of C, 6.9% by weight of Cr, 4.25 by weight of t Si, 3.2 wt -.% B, 3 wt .-% Fe and the balance nickel and

(3) 50% by weight of a cobalt-based alloy and 50% by weight of tungsten carbide, where the cobalt alloy consists of 1.5% by weight B, 25% by weight. Cr, 1.5% by weight C, 4% by weight W, 3% by weight Ni and for Rest of cobalt.

The fact that a matrix metal, for example cobalt, which contains metal carbides (primary carbides) has good thermal conductivity is known per se. For example, a sintered WC-Co mass with 12% by weight of cobalt has a thermal conductivity of 0.16 / cm ² / cm / ° C. / sec. on.

line essential property of an applied to a metal substrate Layer is based on its resistance to Peeling or chipping. It has been found to be desirable if the relative expansion coefficient between the final coating and the ferrous metal substrate is + 50% and -301. Assume that the ferrous metal substrate has a coefficient of expansion at room temperature of about 11 10 "" inch / inch / ° C has, the alloy layer may have an expansion coefficient from about 7.7 to about 10 or 17 χ 10 in / in / ° C, provided that the alloy layer is metallurgically applied to the lii metal substrate is bound.

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Claims (9)

PATENTANWÄLTE Reg.No. 12! 54.5 U (O / H4 (O Cl H.Bartels Dipl.-Chem. Dr. Brandes LUTECTIC CORPORATION, Flushing, New York / USA 8 Munich 22. Thierschstrasse 8 Process to improve wear and tear Tel. (089) 293297, c.,...,,.. .. Telex 0523325 (patwo d) share properties of ferrous metal Telegram address: wolffpatent, munich Postscheckkonto Stuttgart 7211 (bank code 60010070) Deutsche Bank AG, 14/28630 (bank code 60070070) Office hours: 8 a.m. to 12 p.m., 1 p.m. to 4.30 p.m. except Saturdays Patent claims Sept. 26, 1977 25/93 1. A method for improving the wear properties of ferrous metal parts with a thermal, measured at room temperature conductivity with respect to silver of at least 0.06 Kai./ cm / cm / ° C / sec., If the conductivity of the silver is set at 1, by generating a 0.0127 to 0.3810 cm thick protective layer of a self-fluxing heat and corrosion resistant alloy based on a metal of the iron group or copper-based, characterized in that, starting on the iron metal parts of an alloy containing up to 30 wt -.% W, Mo and / or Cr and optionally 0.1 to 6% by weight of Si and to which up to 3% by weight of C and / or 0.5 to 5% by weight of B is added, the content being added at B and / or C so that at least 70 % of the metals W, Mo and Cr are bonded in the form of secondary borides and / or secondary carbides, a protective layer with a thermal conductivity with respect to silver measured at room temperature, if the conductivity ability of silver is set at 1, of at least 0.05 cal / cm / cm / ° C / sec. generated. 2. The method nacli claim 1, characterized in that there is used a copper-based alloy, to which 10 to 40 wt -.% Of Ni, 1 to 5 parts by I Si, 0.1 to 2.5 wt .-% B, 0.2 to 2 wt .-% Mn and the remainder of copper. 8098U / 0856 ORIGINAL INSPECTED - 2 - 27U189 3. Process according to Claims 1 and 2, characterized in that a protective layer is produced which, based on the weight of the protective layer, contains up to 8% by weight of primary carbides of Ii, Zr, Hf, V, Nb, Ta, Cr, Mo and / or W contains. 4. The method according to one of claims 1 to 3, characterized in that that an alloy based on Ni, Co, Fe or Cu is used and a protective layer 0.0254 to 0.203 cm thick is produced. 5. The method according to claim 3, characterized in that one produces a Schutzscliicht containing 5 to 70 wt -.% Contains primary carbides. 6. The method according to claims 3 and 5, characterized in that a protective layer is produced, which is tungsten carbide as the primary carbide contains. 7. The method according to claim 6, characterized in that one Protective layer created as a primary carbide tungsten carbide Contains particle size less than 100 microns. 8. Ferrous metal part with a thermal conductivity with respect to silver, measured at room temperature, of at least 0.06 Kai./cm / cm / ° C / sec., If the conductivity of the silver is set at 1, which is 0.0127 to improve its wear properties up to 0.3810 cm thick protective layer made of a self-running heat and corrosion-resistant alloy based on a metal of the iron group or based on copper, characterized in that it has a protective layer with a thermal conductivity measured at room temperature with respect to silver, if the conductivity of the silver with 1 is set, of at least 0.05 quays / cm / cm / ° C / sec. of an alloy containing up to 30 wt · W, Mo and / or Cr, as well as optionally 0.1 to 6 parts by weight of Si and I get up to 5 parts by t C and / or 0.5 to 5% by weight of B is added, the content of B and / or C being measured so that at least 70 % of the metals W, Mo and Cr are present in bonded form in the form of secondary borides and / or secondary carbides. 8098U / 0856 ^"3 - 274A189 gen, has. 9. Eisenmetalltei1 according to claim 8, consisting of a heat exchange e r e 1 c nie η t. 8098 U / 0856